1. Technical Field
The present invention relates to a driving force controller for a vehicle which selects one driving force characteristic from a plurality of different driving force characteristics by manipulation (outside operation) and determines driving force based on the selected driving force characteristic.
2. Related Art
According to a so-called electronic control throttle type engine which electrically controls a throttle valve known in the art, an accelerator pedal and the throttle valve are not mechanically linked. Thus, the opening of the throttle valve (throttle opening) can be non-linearly controlled for the operating amount of the accelerator pedal (accelerator opening).
For example, a technology disclosed in JP-A-2005-188384 divides the driving condition of the engine into a plurality of driving ranges based on engine rotational speed and accelerator opening and creates a map for each of the driving ranges so as to control the opening of the throttle valve in accordance with the operation condition of the engine.
According to the technology disclosed in this reference, excellent driving performance is obtained by increasing potential to the maximum at the time of high-speed running, and driving with reduced power is attained when stopping and running are repeated in such cases as traffic congestion. Thus, excellent drivability can be achieved.
According to the technology shown in the above reference, an appropriate map is automatically selected for each of the driving ranges, and the throttle opening is controlled in accordance with the selected map. In this case, when a vehicle having a high-performance engine such as a turbo engine is running on an ordinary road, the driving range is shifted to a full acceleration range and extremely high acceleration performance is offered by a largest possible amount of operation of the accelerator pedal. Therefore, during running on the ordinary road, it is required that the operation amount of the accelerator pedal is continuously and finely adjusted, which increases nervousness of control over the acceleration.
When power for the engine is excessively reduced, sufficient acceleration is not obtained at the time of high-speed running or running on an upward slope. As a result, the driver feels insufficient power of the vehicle.
For example, a technology disclosed in JP-A-2000-161098 selects one of the automatic transmission shift patterns between normal mode for economic efficiency and the power mode for accelerating performance by an operation for a mode select switch.
According to the technology shown in the above reference, one of power mode and normal node can be selected by ON/OFF operation of the mode select switch. However, if this mode select switch is formed by a push switch type, it is a possibility for causing the incorrect operation such as ON operation or OFF operation. If the mode select switch is operated to select ON state when the vehicle is drove in a normal mode, the transmission shift pattern is changed to the power mode so that the driving force is sudden increased. This change causes the driver's insecurity feeling.